Hydraulic drag saw



Jan. 21, 1947. J. c. GREENE, JR

HYDRAULIC DRAG SAW Filed Dec. 2'7, 1943 3 Sheets-Sheet 1 uvvszvrom JbH/V C. GREENE Jk ATT R/VEY Jan. 21, 1947. J. c. GREENE, JR

HYDRAULIC DRAG SAW Filed Dec. 27, 1943 3 Sheets-Sheet 2 u IIIII/IIJIIIIIIIII/IIIIYi/k/ 1/1110.rllklll zllllm INVEN TOR. CZ GREENE Ja ATTORNEY Jan. 21 1947. J. c. GREENE, JR 2,414,519

HYDRAULIC DRAG SAW Filed Dec. 27, 194:5 3 sheets-Sheet s we a 6a By ATTOEIIEY Patented Jan. 21, 1947 UNITED STATES PATENT OFFICE HYDRAULIC DRAG SAW John C. Greene, Jr., Watertown, Conn.

Application December 27, 1943, Serial No. 515,668

1 Claim. 1

This invention relates to drag saws, and more particularly to a high speed drag saw operated hydraulically by an internal combustion engine.

One object of the invention is to provide a portable light weight drag saw of the above nature which may be conveniently used for felling. bucking, and limbing trees in the manufacture of tcord wood, pulp wood, and similar forest produc s.

. A further object is to provide a drag saw of the above nature in which a hydraulic liquid is alternately pumped by a pair of pistons connected to the engine crank shaft and located in a pair of auxiliary cylinders having conical lower ends, connected to a pair of smaller clylinders within which are a pair of saw-driving pistons joined together by a common connecting rod lnd rigidly attached to the reciprocating saw.

A further object is to provide a hydraulic drive for a drag saw having a conical valve located in the passage between the conical sections of the auxilairy cylinders, said valve having transverse passages for permitting the liquid to bypass between the hydraulic cylinders whenever the saw is stopped by means of the brakes, to be described later.

A further object is to provide a conical bypassing valve of the above nature in which the valve has a threaded'spindle upon the top thereof, said spindle having a ratchet which is actuated step by step by a trigger-operated flexible cable, so that by successive manual actuations of the trigger, the control valve may be opened or closed as desired.

A further object is to provide a device of the above nature in which the valve ratchet is so coordinated with the trigger member that the hypass valve will be rotated successively by quarter turns for twisting said valve to closed, half-closed or open positions.

A further object is to provide a drag saw of the above nature having a pair of upper and lower guiding handles adapted to be grasped during use by the hands of the operator.

A further object is to provide a drag saw of the above nature having a pair of triggers located adjacent the lower handle, one of said triggers being connected by a flexible cable to the engine carburetor and the other trigger being connected to a ratchet arm for operating a bypassing valve.

A further object is to provide guiding means for the saw comprising a pair of channels embracing the upper and lower edges of said saw, and a pair of elongated roller members located on each side of the saw at the forward portion of the saw housing.

A further obect is to provide a manually controlled brake mechanism for stopping the saw whenever desired, without stalling the engine.

A further object is to provide an easily portable dragsaw of the above nature in which the saw may be reciprocated more rapidly through the hydraulic apparatus than was possible in previous devices when the saw was operated mechanically either directly or indirectly from the iently be'embodied in practice.

saw blade is mounted for reciprocation in its housing.

Fig. 5 is a front end view of the saw hOllslIlg,

showing the appearance of the pair of guiding rollers which engage the opposite surfaces of the saw.

Fig. 6 is a longitudinal sectional view of the manually-operated brake f0r temporarily stopping the saw whenever desired.

Fig. 7 is a sectional view on a larger scale. taken along the line '|-l of Fig. 1, showing the construction of the two hydraulic cylinders and the bypass valve located between the conical portions thereof.

Fig. 8 is a similar sectional view, taken along the line 8--8 of Fig. 1, showing the construction of the interior of the-bypass valve.

Fig. 9 is a sectional view, taken along the broken line 9-9 of Fig. 7, and showing the con struction of the trigger-operated ratchet mechanism for closing the bypass valve to start the operation of the saw, and, opening said valve to permit the liquid to bypass between the hydraulic cylinders when the saw is stopped by actuation of the brake.

Referring now to the drawings in which like reference numerals denote corresponding parts throughout the several views, the numerals l0, ll indicate a pair of parallel main cylinders of an air-cooled four-cycle internal combustion engine, said cylinders being preferably cast integrally in a single block indicated by the numeral l2.

Located within the cylinders I0, II are a pair of pistons l3, [4, which are joined by connecting rods l5, l6 to a crank shaft ll, upon which is mounted a flywheel I'Ia, said crank shaft being journaled inbearings llb, I'Ic, I'ld, respectively.

Below th crank shaft ll, provision is ,made of a pair of connecting rods l8, 19, the lower ends of which are joined to a pair of pistons 20, 2| located in the upper cylindrical ends of a pair of hydraulic auxiliary cylinders 22, 23, having conical lower portions 24, 25 (as clearly shown in Fig. 1).

The hydraulic cylinders 22, 23 have outlet openings 26, 21 at their bottom ends, to which are connected a pair of flexible hydraulic conduits- 28, 29-the other ends of said conduits being joined by elbows 30, 3| to a pair of aligned small saw-operating cylinders 32, 33 carried by the movable saw housing 48 to bedescribed later.

The elbows 30, 3| are connected to a pair of enlarged sockets 34, 35, which are integrally joined to the outer ends of the small cylinders 32, 33. The inner ends of the small cylinders are joined to a pair of sockets 36, 31.

Mounted within the cylinders 32, 33, are a pair of small saw-driving pistons 38, 39 connected together by a common connecting rod 40 which reciprocates with the pistons located at the 'ends thereof. The connecting rod 40 is rigidly joined by a set screw 4| to a bracket 42, which inturn is secured by screws 43, 44, 45, 46 to a saw 41.

The saw is mounted to reciprocate within a housing 48 attached by screws 48a to the sockets 34, 35, 36, 31. The housing 48 is furnished with a pair of upper and lower guide channels 49, 50

which have screws 5| for connecting a removable side cover 52 (Figs. 4 and 5) t the saw housing 48. Provision is also made of a rear housing cover 53, which is also removable.

At the front of the saw housing 48, a pair of elongated parallel saw guide rollers 54, 55 (see Figs. 2 and are supplied, said rollers being mounted in alignment with each other and adapted to engage opposite sides of the saw 41.

Provision isalso made; of a pair of slidable wedge blocks 56, 51 fastened to the upper and lower edges of the saw 41, said wedge blocks being embraced by a pair of V-shaped bearings 58, 59, as clearly shown in Fig. 5. The wedge blocks 56, 51 are adapted to be lubricated through a pair of small oil holes 60, 6|, located at the opposite edges of the housing 48 in alignment with the wedge groove bearings 58, 59. 7

'- In order to bypass the hydraulic liquid between the auxiliary cylinders 22, 23, whenever the saw is temporarily stopped, provision is made of a vertical control valve 62 of conical shape (as most clearly shown in Figs. 1 and 8), said valve 62 having four radial passages 63, 64, 65, 66 arranged in the shape of a cross. The valve 62 rotates in a housing 61 having passages 68, 69, leading to the conical portions 24, 25 of the hydraulic, cylinders 22, 23, previously described.

In order to control the operation of the drag saw, provision is made of a pair of trig eve s 10, I l projecting from the bottom of the housing 48, said trigger levers having flexible cables 12, 13 connected thereto (see Fig. 1). The cables 12, 13 are adapted to slide freely in housings 12a, 13a, respectively.

The cable 72 is clamped at its other end to the engine carburetor, not shown. The cable 13 is connected at its other end to a ratchet arm 14, by means of a set screw 15. The arm 14 is connected to a reduced end 16 of a shaftl'l, integral with the bypass valve 62, by a headed lock screw 18. A horizontal ratchet wheel 79 is held rigidly upon the reduced end 16 of the shaft 11 by means of a key pin 80 (see Fig. 9).

The teeth on the ratchet wheel 19 are indicated by the numeral BI, and said teeth are adapted to be engaged by a radially arranged slidable pawl 82 which is pressed inwardlyat all times by a coiled spring 83 located in a socket 84 formed in the ratchet arm I4.

Provision is also made of a series of eight equally spaced countersunk recesses 85 formed in the exterior of the shank of the ratchet Wheel 19, which recesses are adapted to be selectively engaged by a hollow pointed radial plug 86, which is pressed inwardly at all times by a short coiled compression spring 81, the outer end of which engages an adjustable screw plug 88 mounted in the housing 69 of the bypass valve 62.

An elongated coiled tension spring 89 is also provided for connecting the outer end of I the ratchet arm 14 with a post 90 projecting from the conical portion 25 of the hydraulic cylinder 23. The countersunk recesses 85 are mounted 45 apart, so, as to hold the bypass valve 62 selectively in one of three positionsclosed, "halfclosed, or open, as desired.

For the purpose of holding the cable 13 in alignment with the end of the ratchet arm 74, an adjustable clamp 9| is provided, on the conical portion 24 (see Fig. 7).

The saw housing is adapted to be manually guided by means of upper and lower handles 92, 93 (see Fig. 1). The upper handle 92 is pref-lerably vertical, while the bottom handle 93 is inclined rearwardly and has finger notches, as shown. v

The numeral 94 indicates a removable center plate (as shown in Fig. 2), which when removed permits access to the interior of the housing 48.

Brake mechanism l The numeral 95 indicates a stationary brake block (see Fig. 6)

which is rigidly secured to the also slightly shiftable in a longitudinal direction with respect to the stationary brake block 95.

Theblocks 95, 96, on their inner faces, have rigidly secured thereto, sheets 91, 98 of brake lining, which sheets are adapted to engage the opposite faces of the saw to exert friction pressure thereon. A tension spring 99 connects the movable brake member 96 to a fixed post I00 on the inside of the front wall of the saw housing 48. In order to operate the brake to stop the saw,

provision is made of a toggle handle lever I01,

mounted on a pivot pin I02 carried by a pair of brackets I03, I04 (see Fig. 4).

The lever l0l extends inwardly into a curved recess I05 in the movable brake block 96 and has its inner end connected to a pin I06 embedded in said block.

Opezation In use, to operate the saw, it is only necessary to first start the internal combustion engine, release the brake handle lever I01, and then turn the bypass valve to closed position.

The saw 41 will thus be caused'to reciprocate within its wedge bearings 58, 59 and will be guided at its intermediate portion by the rollers 54, 55, said saw being preferably of the type which will cut when moving in both directions.

Whenever it is desired to stop the saw, the trigger -II will be actuated to index the bypass valve 62 into open position. The toggle brake lever lfll will then be swung manually into braking position at right angles to the housing 48.

It will be understood that if desired, the internal combustion engine and attached hydraulic cylinders may be mounted on a pack board and carried on the back of the operator while the saw is being used. 7

While there has been disclosed in this specification one form in which the invention may be embodied, it is to be understood that this form is shown for the purpose of illustration only, and that the invention, is not-to be limited .to the speciflc disclosure, but may be modified and embodied in various other forms, without departing from its spirit. In short, the invention includes all the modifications and embodiments coming within the scope of the following claim:

Having thus fully described the invention what is claimed as new and for whichit is desired to secure Letters Patent is:

In a portable drag saw, a hydraulic pump comprising a pair of parallel spaced cylinders, a bypass passage connecting the ends of said cylinders, a. rotatable valve'in said passage, a pair of powerdriven pistons in said cylinders, a pair of flexible conduits connected to the ends of said cylinders, a saw-carrying frame adapted to be carried by the operator, a pair of aligned saw-driving cylinders located in said frame and connected at their ends to said conduitsa pair of saw-driving pistons in said saw-driving cylinders, said bypass valve having a ratchet wheel connected thereto, a pawl for engaging said ratchet wheel, and manually-operated trigger means associated 

